Battery terminal clamp



Nov. 18, 1952 H. c. LALLMA'NG 2,613,675

BATTERY TERMINAL CLAMP Filed Nov. 14, 1950 H0 ward C Zaflmang L ZINVENTOR.

Patented Nov. 18, 1952 UNI TED STATES PATENT OFFICE 5 Claims.

.This invention relates to battery :cable clamp devices,-and has for oneof :its objects the provision of a novel and improved clamp device ofthe type which is operable to be more quickly and easily clamped andunclamped relative to a battery post for attachment or removaltherefrom.

Another object of the invention is to .provide a clamp device asaforesaid which employs 'a clamping screw of opposite thread type, andwhich is of improved construction wherebythe actuating screw is gearedin improved manner to the lug portions of the clamp device whichstraddle the battery post.

Another object of the invention is to provide an improved clamp deviceas aforesaid which embodies-structural reinforcement means functioningalso as screw engagement means, so as to provide a clamping device ofimproved structural strength.

Other objects of the invention will appear in the specificationhereinafter.

In the drawing, Fig. 1 is a fragmentary top plan view of a storagebattery and terminal post having mounted thereon a cable clamp device ofthe invention; the clamp device being shown in horizontal section; and,

Fig. 2 is a fragmentary section taken along line 11-11 of Fig. 1.

In the drawing a storage battery is indicated fragmentarily at asmounting a terminal post I2 of the conventional circular shape, and aconductor cable for connection to the post I2 is indicated at M. Thecable clamp device is illustrated generally at [5 as comprising abifurcated yokemember It having a shank portion I8 enclosing the'end ofthe cable 14 and a pair of parallel lug portions 20-20 straddling thebattery post 12 and extending therebeyond in substantially parallelrelation to receive the actuating screw member 22. :As is well known inthe battery terminal art, the cable clamp yoke piece It is preferablymolded of lead metal and is circularly socketed .as indicated at 24Yforoptimum electrical contact and connection with the lead post F2 of thebattery. I

Thescrew member '22 is provided with opposite- 1y pitched threadportions 2628 at opposite ends thereof and in the regions of itsmounting within the lug portions 20-20 of the yoke member; I

and as is also well known in the art, the screw member 22 is preferablyformed of steel or some other relatively strong metal and preferablygalvanized or otherwise plated soas to be of maximum strength againstthe possibility of --strip ping of the threads of the crew duringoperation thereof. As indicated at 30, one end of the screw is arrangedto extend beyond the clamp device to enable-the screw to be" gripped bysome suitable :tool for rotating the latter. Thus, the endpor tionflilof the screwmember may be simply squared or otherwise shaped-so as toreadily receive an adjustable wrench'or'other such tool formanipulationof 'the'scr'ew; or,-as shown in the drawing, the end portion 30 may beserrated and a lever "32 having a similarly serrated bore portion may beslip-fitted on the serrated endof the screw, so that no separate toolwill be requiredto operate the device.

Thus, whereas Fig. 1 illustrates the cable clamp device in mountedposition upon the post l'2, it will be'understood that simple rotationof the handle '32 Willcause the screw to rotate in such manner as toforce the two lug portions 2ll---'2il of the clamp device tomove apart;th'us'freeing the'clamp device from the'batterypost 12. Thus, the'clampdevice may with utmost ease and convenience be quickly released from thebattery post without need of bungling attempts at fitting some tool tothe device for release of the clamping action. Furthermore, it will beappreciated that inasmuch as the thread portions 2E-28 on the screwdevice areof oppositely directed form, a minimum degree of rotation ofthe screw 22 will result in suflicient spreading displacement of the lugportions 20-26 to completely free the clamp device from the batterypost. Similarly, in connection wit-hcableattachment operations, theclamp device in spread-apart form may be simply slip fitted downwardlyupon the terminal post 12, and. then a flip of the handle 32 in theopposite direction will cause the screw device to draw the lug portions20-4!) inwardly toward one another so as to firmly clamp the device uponthe battery .post in response to a minimum degree'of rotation of thescrew. Inasmuch as the handle member 32 may be freely slip-fitted offand on the serrated end portion of the screw, it will be appreciatedthat the device is readily ad;- justable to take care of dimensionaldifferences-in the yoke constructionand in the size of the battery poststo be connected.

Whereas it is well known that lead metal is greatly to be preferred inthe construction of the yoke portions of such clamp devices because ofthe superior electrical connections and resistance to corrosion therebyprovided, it is also a fact that leadmetal-in itself is relatively softand malleable and therefore notinherentlysuited to take any substantialforces in bending or in shear. Consequently battery terminal clampdevices which are constructed solely of lead metal tend to plasticallydeform at the extending lug portions thereof whenever a locking bolt orthe like is applied thereto for the purposes of drawing the lug endsinwardly to clamp the device upon the battery post. Also, any lead metalscrew thread formations are inherently weak and lacking in adequateresistance to stripping in a battery clamp device because of theweakness of lead metal to resist forces in shear. Hence, it will beappreciated that any cable clamp device of the nature referred tohereinabove which would employ a reversely threaded screw member as inthe case of the drawing would not be practicable if it relied solelyupon the formation of screw threads within the lead lug portions.Therefore, it is a particular feature and advantage of the presentinvention that the yoke and lug portions of the clamp device of theinvention is internally reinforced by means of a wish-bone shaped metalbackbone element which functions to reinforce the lug portions of theclamp device against plastic deformation and bending and which at thesame time reinforces the screw thread formations within the lug membersand protects the screw thread structures of the lug elements againststripping. At the same time, the novel arrangement of the inventionfacilitates ease of initial assembly and manufacture of the clamp deviceas will be explained hereinafter, and thus the clamp device of theinvention may be easily manufactured in accord with most economicalmanufacturing procedures.

More specifically, as shown in the drawing, the novel reinforcing deviceof the invention is illustrated to comprise a spring steel member ofgenerally wishbone shape having a pair of leg portions 344 which areembedded in the leg portions 2l-20 of the clamp device; the leg portionslid-3t uniting and terminating in a collar portion 36 which is embeddedin the shank portion l8 of the clamp device and encircles the extremeend of the cable I l. Adjacent their outer ends the leg portions 343lare bored in alignment as indicated at 3838 to diameters suitable toreceive the thread portions 2G28 of the screw member in freely slidingrelation therethrough during initial assembly of the device.

Thus, to manufacture the clamp of the invention, the backbone member isfirst slip fitted at its collar portion 36 over the end of the cable l4,and the collar portion is then swaged inwardly against the cable so asto firmly connect thereon. The cable and backbone unit is then placed ina suitable mold for pouring of the lead metal to enclose the backbonemember; the screw 22 being first slip fitted endwise through theopenings 3S38 in the legs 34-34. Then, the screw member 22 is movedrearwardly in the backbone member, or toward the left as viewed in Figs.1, 2, into the position thereof shown in Fig. 1 so that the screwformations 2828 engage in geared relation with the rear edges of theapertures 3838 through the leg portions 34-34. Then, molten lead ispoured into the mold so as to complete the molded clamp structure to theshape as indicated in the drawing with the backbone member and the screwmember both mounted therein. Thus, it Will be appreciated that the screwmember may now be rotated as explained hereinabove, and t that thegeared connection between the steel screw threads and the steel backbonemember will take the shear loads which would otherwise be imposed uponthe molded lead lug structures so as to prevent stripping of the leadthreads. Also it will be appreciated that the spring steel leg portions3434 will reinforce the lead lug portions 2020 against plasticdeformations thereof incidental to applications of the cable device to abattery terminal and will in effect provide the latter with resilientcharacteristics tending to maintain their normal shapes in improvedmanner.

To facilitate the lead molding process and operation of the device, Iprefer to coat the screw parts 2628 with some suitable lubricant orparting material prior to the lead pouring operation, so as to preventthe lead from sticking to the screw parts in such manner as wouldinterfere with easy rotation of the screw for clamp adjustment purposes.For example, an oil or grease or graphite base substance may be employedfor such purpose.

Whereas the handle 32 is shown in the drawing as being detachable fromthe screw 22, it may of course be permanently fixed thereto if preferredso that there is assurance that the handle will be at all times inreadiness for operation as for example in event it is necessary toquickly disconnect the cable from the battery in case of a short circuitcondition.

It will of course be appreciated that whereas only one specific form ofthe invention has been shown and illustrated "in detail, the inventionis not so limited and that various changes may be made therein withoutdeparting from the spirit of the invention and the scope of the appendedclaims.

I claim:

1. A cable clamp for connection to a battery post, said clamp comprisinga lead metal body of split form adapted to straddle a battery post andincluding a pair of lugs projecting therefrom with aligned screwthreadedapertures therethrough, ferrous metal insert means imbedded in each ofsaid lugs, a screw extending transversely through said lugs and havingoppositely threaded portions mounted in screw threaded relation therein,said insert means being apertured to diameters greater than the diameterof the threaded portions of said screw and on centers offset from thecenters of the screwthreaded apertures through said lugs, said screwextending through said insert means eccentrically of the aperturestherethrough and thereby disposed in geared relation with edge portionsthereof.

2. A cable clamp for connection to a battery post, said clamp comprisinga lead metal body of bifurcated form adapted to straddle a battery postand including a pair of lug portions projecting therebeyond with alignedscrewthreaded apertures therethrough, a fork shaped spring metal insertmeans imbedded in said body, a screw extending transversely through saidlug portions and having oppositely screw threaded portions thereofmounted in screw threaded relation in said lug portions, said insertmeans being apertured in the regions of said lug portions to diametersgreater than the diameter of the threaded portion of said screw and oncenters offset from the centers of the screwthreaded apertures throughsaid lugs, said screw extending through said insert means eccentricallyof the apertures therethrough and thereby disposed in geared relationwith edge portions thereof.

3. A cable clamp for connection to a battery post, said clamp comprisinga lead metal body of fork form adapted to straddle a battery post andincluding a pair of lug portions projecting therebeyond with alignedscrewthreaded apertures therethrough, spring metal insert means of forkshape imbedded in said body and including opposite leg portions disposedwithin said lug portions, a screw mounted to extend between andtransversely through said lug portions and having oppositely screwthreaded portions thereof mounted in screw threaded relation therein,said insert leg portions being apertured to diameters greater than thediameter of the threaded portions of said screw and on centers oflsetfrom the centers of the screwthreaded apertures through said lugs, saidscrew extending through said insert leg apertures eccentrically of theapertures therethrough and thereby disposed in geared relation with edgeportions thereof.

4. A cable clamp for connection to a battery post, said clamp comprisinga soft metal body of bifurcated form adapted to straddle a battery postand including a pair of lug portions projecting therebeyond with alignedscrewthreaded apertures therethrough, a fork shaped hard metal insertimbedded in said body, a screw extending transversely through said lugportions and having oppositely screw threaded portions thereof mountedin screw threaded relation in said lug portions, said insert beingapertured in the regions of said lug portions to a diameter greater thanthe diameter of the threaded portions of said screw and on centersoffset from the centers of the screwthreaded apertures through saidlugs, said screw extending through said insert and eccentrically of theapertures therethrough and thereby disposed in geared relation with edgeportions thereof, said screw being serrated at an extending end portionthereof, and a handle adapted to slip fit upon said screw serrated endportion 5. A cable clamp for connection to a battery post, said clampcomprising a soft metal body of fork form adapted to straddle a batterypost and including a pair of lug portions projecting therebeyond withaligned screwthreaded apertures therethrough, hard metal insert means offork shape imbedded in said body and including opposite leg portionsdisposed within said lug portions, a, screw mounted to extend betweenand transversely through said lug portions and having oppositely screwthreaded portions thereof mounted in screw threaded relation therein,said insert leg portions being apertured to diameters greater than thediameter of the threaded portions of said screw and on center offsetfrom the centers of the screw threaded apertures through said lugs, saidscrew extending through said insert leg apertures and eccentrically ofthe apertures therethrough and thereby disposed in geared relation withedge portions thereof, and an operating handle attached to one end ofsaid screw for actuation thereof.

HOWARD C. LALLMANG.

REFERENCES CITED The following references are of record in the file ofthis patent:

